Know your formats
Supported formats and limitations
- Input formats
- JSON
- Output formats
- CSV
- Missing and null fields become empty cells. Duplicate keys use the last value. Numbers use browser precision and unsafe integers are rejected.
- Formula-like cells get a leading apostrophe in the CSV export.
A nonempty array of objects becomes one header row followed by records. Columns are the union of top-level keys. Nested arrays and objects become compact JSON text in one cell, while missing and null fields become empty. Unsafe integers are rejected, and spreadsheet safety may add an apostrophe to a field.
Maximum input size is 2 MiB per file.
A local workflow
How to use this converter
Your file contents stay in the browser as you work.
Select the JSON file.
Convert the records into a table.
Save the CSV and review any formula-safety notice.
A little more clarity
Frequently asked questions
What happens to nested arrays and objects?
They are serialized as compact JSON inside their own CSV cells, retaining the nested structure.
Is JSON to CSV available now?
This tool runs locally with JavaScript enabled. Check its supported formats and size limits before converting.